ScriptedImporter overrides internal Importer

I am trying to create a ScriptedImporter for *.po files (gettext localization). Unfortunately, there is already an internal importer for this file type. This is inaccessible and the asset type (LocalizationAsset) can only be used inside the editor. Is there a way to override internal importers with custom ScriptedImporter? I like to have po files being included in AssetBundles (without renaming them), streamlining the versioning and caching of remote localizations to all other asset types.